Abstract:
:Interstellar dust is responsible, through surface reactions, for the creation of molecular hydrogen, the main component of the interstellar clouds in which new stars form. Intermediate between small, gas-phase molecules and dust are the polycyclic aromatic hydrocarbons (PAHs). Such molecules could account for 2-30% of the carbon in the Galaxy, and may provide nucleation sites for the formation of carbonaceous dust. Although PAHs have been proposed as the sources of the unidentified infrared emission bands that are observed in the spectra of a variety of interstellar sources, the emission characteristics of such molecules are still poorly understood. Here we report laboratory emission spectra of several representative PAHs, obtained in conditions approximating those of the interstellar medium, and measured over the entire spectral region spanned by the unidentified infrared bands. We find that neutral PAHs of small and moderate size can at best make only a minor contribution to these emission bands. Cations of these molecules, as well as much larger PAHs and their cations, remain viable candidates for the sources of these bands.
journal_name
Naturejournal_title
Natureauthors
Cook DJ,Schlemmer S,Balucani N,Wagner DR,Steiner B,Saykally RJdoi
10.1038/380227a0subject
Has Abstractpub_date
1996-03-21 00:00:00pages
227-9issue
6571eissn
0028-0836issn
1476-4687journal_volume
380pub_type
杂志文章相关文献
NATURE文献大全abstract::Modifications of histone proteins have essential roles in normal development and human disease. Recognition of modified histones by 'reader' proteins is a key mechanism that mediates the function of histone modifications, but how the dysregulation of these readers might contribute to disease remains poorly understood....
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/s41586-019-1842-7
更新日期:2020-01-01 00:00:00
abstract::Reinforcement learning models postulate that neurons that release dopamine encode information about action and action outcome, and provide a teaching signal to striatal spiny projection neurons in the form of dopamine release1. Dopamine is thought to guide learning via dynamic and differential modulation of protein ki...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/s41586-020-03050-5
更新日期:2020-12-23 00:00:00
abstract::The gene encoding the large-T protein of polyoma virus (plt), the E1A genes of adenoviruses, the viral myc gene (v-myc) or rearranged forms of the cellular c-myc gene confer on rat embryo fibroblast (REF) cells in primary culture a series of new properties ('immortality', reduced serum requirement and sensitivity to t...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/314277a0
更新日期:1985-03-21 00:00:00
abstract::Obesity is a disorder of energy balance, indicating a chronic disequilibrium between energy intake and expenditure. Recently, the mouse ob gene, and subsequently its human and rat homologues, have been cloned. The ob gene product, leptin, is expressed exclusively in adipose tissue, and appears to be a signalling facto...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/377527a0
更新日期:1995-10-12 00:00:00
abstract::Since the discovery of superconductivity in the high-transition-temperature (high-T(c)) copper oxides two decades ago, it has been firmly established that the CuO(2) plane is essential for superconductivity and gives rise to a host of other very unusual properties. A new family of superconductors with the general comp...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature07081
更新日期:2008-06-26 00:00:00
abstract::Recent studies have shown that normal cellular sequences on chromosome 13 are lost during the development of retinoblastomas and that sequences on chromosome 11 are similarly lost during the development of Wilms' kidney tumours and embryonal tumours. Cells from these tumors have been found to contain either the patern...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/318377a0
更新日期:1985-11-28 00:00:00
abstract::Studies of the actin-based motility of the intracellular pathogens Listeria monocytogenes and Shigella flexneri have provided important insight into the events occurring at the leading edges of motile cells. Like the bacteria Listeria and Shigella, vaccinia virus, a relative of the causative agent of smallpox, uses ac...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/44860
更新日期:1999-10-28 00:00:00
abstract::Cryptosporidium species cause acute gastroenteritis and diarrhoea worldwide. They are members of the Apicomplexa--protozoan pathogens that invade host cells by using a specialized apical complex and are usually transmitted by an invertebrate vector or intermediate host. In contrast to other Apicomplexans, Cryptosporid...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature02977
更新日期:2004-10-28 00:00:00
abstract::Mutations in phosphatase and tensin homologue (PTEN) or genomic alterations in the phosphatidylinositol-3-OH kinase-signalling pathway are the most common genetic alterations reported in human prostate cancer. However, the precise mechanism underlying how indolent tumours with PTEN alterations acquire metastatic poten...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature11674
更新日期:2013-01-10 00:00:00
abstract::T-cell receptor-induced apoptosis regulates immune responses and can result from interactions between Fas (Apo1/CD95) and Fas ligand (FasL). Mutations in the genes for Fas and FasL cause disorders resembling human autoimmune diseases in lpr and gld mice, respectively. However, peripheral T-cell deletion takes place in...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/377348a0
更新日期:1995-09-28 00:00:00
abstract::The majority of human emerging infectious diseases are zoonotic, with viruses that originate in wild mammals of particular concern (for example, HIV, Ebola and SARS). Understanding patterns of viral diversity in wildlife and determinants of successful cross-species transmission, or spillover, are therefore key goals f...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature22975
更新日期:2017-06-29 00:00:00
abstract::Accurate measurement of the lifetime of the neutron (which is unstable to beta decay) is important for understanding the weak nuclear force and the creation of matter during the Big Bang. Previous measurements of the neutron lifetime have mainly been limited by certain systematic errors; however, these could in princi...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/47444
更新日期:2000-01-06 00:00:00
abstract::Quantum superposition lies at the heart of quantum mechanics and gives rise to many of its paradoxes. Superposition of de Broglie matter waves' has been observed for massive particles such as electrons, atoms and dimers, small van der Waals clusters, and neutrons. But matter wave interferometry with larger objects has...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/44348
更新日期:1999-10-14 00:00:00
abstract::With the discovery1 of superconductivity at 203 kelvin in H3S, attention returned to conventional superconductors with properties that can be described by the Bardeen-Cooper-Schrieffer and the Migdal-Eliashberg theories. Although these theories predict the possibility of room-temperature superconductivity in metals th...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/s41586-019-1201-8
更新日期:2019-05-01 00:00:00
abstract::Few intergalactic, plausibly primordial clouds of neutral atomic hydrogen (H(i)) have been found in the local Universe, suggesting that such structures have either dispersed, become ionized or produced a stellar population on gigayear timescales. The Leo ring, a massive (M(H(i)) approximately 1.8 x 10(9)M[symbol: see ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature07780
更新日期:2009-02-19 00:00:00
abstract::The guanine nucleotide-binding stimulatory protein (Gs) couples hormone-receptor interaction to the activation of adenylate cyclase and the generation of cyclic AMP. Studies using frog neuroepithelium indicate that the sense of smell is mediated by a Gs-adenylate cyclase system, and this prompted us to test olfaction ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/322635a0
更新日期:1986-08-14 00:00:00
abstract::Specific chromosomal deletions sometimes associated with tumours such as retinoblastoma (chromosome 13q14) and Wilm's tumour (chromosome 11p13) have led to the hypothesis that recessive genes may be involved in tumorigenesis. This hypothesis is supported by demonstration of allele loss specific for these regions using...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/329451a0
更新日期:1987-10-01 00:00:00
abstract::The pathways that control insulin secretion and regulate pancreatic beta-cell mass are crucial in the development of diabetes mellitus. Maturity-onset diabetes of the young comprises a number of single-gene disorders affecting pancreatic beta-cell function, and the consequences of mutations in these genes are so serio...
journal_title:Nature
pub_type: 杂志文章,评审
doi:10.1038/414788a
更新日期:2001-12-13 00:00:00
abstract::Understanding exotic forms of magnetism in quantum mechanical systems is a central goal of modern condensed matter physics, with implications for systems ranging from high-temperature superconductors to spintronic devices. Simulating magnetic materials in the vicinity of a quantum phase transition is computationally i...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature09994
更新日期:2011-04-21 00:00:00
abstract::Lymphocyte function-associated antigen-1 (LFA-1) is a heterodimer composed of an alpha and beta chain that is expressed on the surface of most leukocytes and is an essential molecule for adhesion reactions between cells participating in the immune response. A putative ligand for LFA-1 is the intercellular adhesion mol...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/333850a0
更新日期:1988-06-30 00:00:00
abstract::The injection of Rous sarcoma virus (RSV) into the wing web of newly hatched chicks causes a rapidly growing sarcomatous tumour which is palpable within 1 week of inoculation; and cultures of fibroblasts derived from chick embryos (CEF) and infected with RSV become rapidly transformed. Genetic studies have determined ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/309552a0
更新日期:1984-06-07 00:00:00
abstract::Unlike the electroweak sector of the standard model of particle physics, quantum chromodynamics (QCD) is surprisingly symmetric under time reversal. As there is no obvious reason for QCD being so symmetric, this phenomenon poses a theoretical problem, often referred to as the strong CP problem. The most attractive sol...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature20115
更新日期:2016-11-03 00:00:00
abstract::Organisms use endogenous clocks to anticipate regular environmental cycles, such as days and tides. Natural variants resulting in differently timed behaviour or physiology, known as chronotypes in humans, have not been well characterized at the molecular level. We sequenced the genome of Clunio marinus, a marine midge...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature20151
更新日期:2016-12-01 00:00:00
abstract::Observations from Earth-orbiting satellites have been a key component in monitoring climate change for the past two decades. This has become possible with the availability of air temperatures from the Microwave Sounding Unit (MSU) since 1979, sea surface temperatures from the Advanced Very High Resolution Radiometer (...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/35000184
更新日期:2000-01-27 00:00:00
abstract::Excision of introns from nuclear precursors to messenger RNAs (pre-mRNAs) by the spliceosome requires two distinct phosphodiester transfer (transesterification) reactions: exchange of a 3'-5' for a 2'-5' bond in the first step (lariat formation) and exchange of one 3'-5' phosphodiester for another in the second step (...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/365364a0
更新日期:1993-09-23 00:00:00
abstract::Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has infected 78 million individuals and is responsible for over 1.7 million deaths to date. Infection is associated with development of variable levels of antibodies with neutralizing activity that can protect against infection in animal models1,2. Antibody ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/s41586-021-03207-w
更新日期:2021-01-18 00:00:00
abstract::DNA fragments of chemically transformed and normal avian and murine cells induce transformation of NIH 3T3 mouse cells with low efficiencies. High molecular weight DNAs of cells transformed by DNA fragments induce transformation with high efficiencies in secondary transfection assays. It thus seems that endogenous tra...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/284418a0
更新日期:1980-04-03 00:00:00
abstract::Werner's syndrome (WS) is a rare autosomal recessive disease in which the affected individuals display symptoms of premature ageing. The substantial phenotypic overlap between WS and normal ageing indicates that these two conditions may have pathogenetic mechanisms in common. The WS mutation has pleiotropic effects, a...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/355735a0
更新日期:1992-02-20 00:00:00
abstract::Non-small-cell lung cancer is the leading cause of cancer-related death worldwide. Chemotherapies such as the topoisomerase II (TopoII) inhibitor etoposide effectively reduce disease in a minority of patients with this cancer; therefore, alternative drug targets, including epigenetic enzymes, are under consideration f...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature14122
更新日期:2015-04-09 00:00:00
abstract::The RAD3 gene of Saccharomyces cerevisiae is required for excision repair of ultraviolet-damaged DNA and is essential for cell viability. The RAD3-encoded protein shares a high degree of homology with the human ERCC2(XPD) gene product. Mutations in XPD, besides causing the cancer-prone syndrome xeroderma pigmentosum, ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/367091a0
更新日期:1994-01-06 00:00:00