Abstract:
:One of the serious limitations of tokamaks as reactors is the occurrence of disruptions. Stellarators designed by advanced computational methods provide an attractive alternative for a major experiment in magnetic fusion research. Configurations with approximate two-dimensional magnetic symmetry have been found with high beta limits and good transport. Specifications are given for a compact stellarator with three field periods and 18 moderately twisted modular coils that has equilibrium with robust flux surfaces, a deep magnetic well assuring favorable stability, and adequate confinement of hot particles at reactor conditions. Fast computer codes with sufficient accuracy to resolve the mathematical problems of equilibrium, stability and transport that arise in the more complicated geometry of the stellarator have produced this breakthrough. The mathematical analysis of the methods used is presented.
journal_name
Proc Natl Acad Sci U S Aauthors
Garabedian PRdoi
10.1073/pnas.97.3.972keywords:
subject
Has Abstractpub_date
2000-02-01 00:00:00pages
972-7issue
3eissn
0027-8424issn
1091-6490journal_volume
97pub_type
杂志文章abstract::Somatostatin (somatotropin release-inhibiting factor; SRIF) is a tetradecapeptide present in brain, pancreas, gastrointestinal tract, and thyroid that inhibits the secretion or action of several hormones in these tissues. We observed that the toad urinary bladder contains concentrations of endogenous somatostatin (8.0...
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.77.8.4984
更新日期:1980-08-01 00:00:00
abstract::Replication of the kinetoplast DNA (kDNA) minicircle of trypanosomatids initiates at a conserved 12-nt sequence, 5'-GGGGTTGGTGTA-3', termed the universal minicircle sequence (UMS). A sequence-specific single-stranded DNA-binding protein from Crithidia fasciculata binds the heavy strand of the 12-mer UMS. Whereas this ...
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.92.23.10511
更新日期:1995-11-07 00:00:00
abstract::The balance between cell survival and cell death is critical for normal lymphoid development. This balance is maintained by signals through lymphocyte antigen receptors and death receptors such as CD95/Fas. In some cells, ligating the B cell antigen receptor can protect the cell from apoptosis induced by CD95. Here we...
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.111158598
更新日期:2001-06-05 00:00:00
abstract::Recombination between unirradiated chromosomes was induced by UV or x-ray irradiation of haploids followed by a mating with heteroallelic diploids of Saccharomyces cerevisiae. The selected event of intragenic recombination did not involve the participation of the irradiated chromosome and apparently was not caused by ...
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.74.4.1667
更新日期:1977-04-01 00:00:00
abstract::Coastal hypoxia (dissolved oxygen ≤ 2 mg/L) is a growing problem worldwide that threatens marine ecosystem services, but little is known about economic effects on fisheries. Here, we provide evidence that hypoxia causes economic impacts on a major fishery. Ecological studies of hypoxia and marine fauna suggest multipl...
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.1617948114
更新日期:2017-02-14 00:00:00
abstract::The number of x-irradiated mammalian cells surviving is markedly increased when the cells are incubated with an uncoupler of oxidative phosphorylation prior to or immediately after irradiation. This increase is greater in plateau-phase cells than in exponentially growing cells. The increase in survival is related to 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.77.5.2702
更新日期:1980-05-01 00:00:00
abstract::Abnormal H2O2 levels are closely related to many diseases, including inflammation and cancers. Herein, we simultaneously load HRP and its substrate, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), into liposomal nanoparticles, obtaining a Lipo@HRP&ABTS optical nanoprobe for in vivo H2O2-responsive chrom...
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.1701976114
更新日期:2017-05-23 00:00:00
abstract::Researchers have documented many cases in which individuals rationalize their regrettable actions. Four experiments examine situations in which people go beyond merely explaining away their misconduct to actively deceiving themselves. We find that those who exploit opportunities to cheat on tests are likely to engage ...
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.1010658108
更新日期:2011-09-13 00:00:00
abstract::The improvement of motor behavior, based on experience, is a form of learning that is critically dependent on the cerebellum. A well studied example of cerebellar motor learning is short-term saccadic adaptation (STSA). In STSA, information on saccadic errors is used to improve future saccades. The information optimiz...
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.0706032105
更新日期:2008-05-20 00:00:00
abstract::The feeling of being observed or merely participating in an experiment can affect individuals' behavior. Referred to as the Hawthorne effect, this inconsistently observed phenomenon can both provide insight into individuals' behavior and confound the interpretation of experimental manipulations. Here, we pursue both 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.1301687110
更新日期:2013-09-17 00:00:00
abstract::A debate has recently surfaced concerning the degree of precommitment attained by alpha beta and gamma delta T-cell precursors prior to T-cell receptor (TCR) gene rearrangement. It has been suggested that precursors may be precommitted to rearrange either alpha or delta genes, but not both, thus giving rise to alpha b...
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.87.14.5583
更新日期:1990-07-01 00:00:00
abstract::We have designed three zinc-finger proteins with different DNA binding specificities. The design strategy combines a consensus zinc-finger framework sequence with previously characterized recognition regions such that the specificity of each protein is predictable. The first protein consists of three identical zinc fi...
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.90.6.2256
更新日期:1993-03-15 00:00:00
abstract::Sca-1 (stem cell antigen-1) enriches for murine prostate cells capable of regenerating tubular structures containing basal and luminal cell lineages in a dissociated cell prostate regeneration system. Sca-1(+) fractions are enriched for cells at the G(0) stage of the cell cycle, and Sca-1(+) cells cluster in the proxi...
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.0502320102
更新日期:2005-05-10 00:00:00
abstract::After collision with their host cells, virus particles may remain mobile on cell surfaces until they become attached at firm binding sites. We propose that a virion will arrive within a typical median time at such a site, generating a membrane signal such as an increased membrane fluorescence in cells labeled with 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.78.9.5618
更新日期:1981-09-01 00:00:00
abstract::It is shown that polyphosphates are not generated in significant amounts in the phosphoglycerate kinase reaction; polyphosphate is more effective than ATP in the formation of glucose 6-P by glucokinase, but the rate with ATP may be adequate to meet the requirements of glucose metabolism; PPi is far more effective than...
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.82.2.312
更新日期:1985-01-01 00:00:00
abstract::A cDNA sequence coding for murine granulocyte colony-stimulating factor (G-CSF) has been isolated from a cDNA library prepared with mRNA derived from murine fibrosarcoma NFSA cells, which produce G-CSF constitutively. Identification of murine G-CSF cDNA was based on the cross-hybridization with human G-CSF cDNA under ...
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.83.20.7633
更新日期:1986-10-01 00:00:00
abstract::Many experiments have been done to determine how far and how freely holes can move along the stack of base pairs in DNA. The results of these experiments are usually described in terms of a parameter beta under the assumption that it describes an exponential decay with distance. The reported values range from beta < 0...
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.050074497
更新日期:2000-04-25 00:00:00
abstract::The prgB gene encodes the surface protein, Asc10, which mediates cell aggregation, resulting in high-frequency conjugative transfer of the pheromone-inducible tetracycline-resistance plasmid pCF10 in Enterococcus faecalis. Messenger RNA analysis by Northern blot hybridization and primer extension indicates that prgB 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.89.19.9020
更新日期:1992-10-01 00:00:00
abstract::A complex between soluble dextran and human hemoglobin has been synthesized by two different methods. In the alkylation method, hemoglobin was allowed to react with bromoacetyl groups incorporated into the dextran; the yield of the complex was about 80% in terms of the hemoglobin used. In the dialdehyde method, hemogl...
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.73.6.2128
更新日期:1976-06-01 00:00:00
abstract::Five peptides corresponding to amino acid sequences predicted from all three reading frames of the nucleotide sequence of the third internal repeat array (IR3) of the Epstein-Barr virus (EBV) genome were synthesized chemically. All five peptides elicited antipeptide antibodies in rabbits. The antiserum raised against ...
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.81.15.4652
更新日期:1984-08-01 00:00:00
abstract::Ras is a guanine nucleotide-binding protein that cycles between inactive GDP-bound and active GTP-bound states to regulate a diverse array of cellular processes, including cell growth, apoptosis, and differentiation. The guanine nucleotide-bound state of Ras is tightly maintained by regulatory factors to promote regul...
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.1037299100
更新日期:2003-05-27 00:00:00
abstract::Cyclin E is an important regulator of cell cycle progression that together with cyclin-dependent kinase (cdk) 2 is crucial for the G1/S transition during the mammalian cell cycle. Previously, we showed that severe overexpression of cyclin E protein in tumor cells and tissues results in the appearance of lower molecula...
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.93.26.15215
更新日期:1996-12-24 00:00:00
abstract::Food avoidance learning in the mollusc Pleurobranchaea entails reduction in the responsiveness of key brain interneurons in the feeding neural circuitry, the paracerebral feeding command interneurons (PCNs), to the neurotransmitter acetylcholine (AcCho). Food stimuli applied to the oral veil of an untrained animal dep...
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.83.12.4556
更新日期:1986-06-01 00:00:00
abstract::According to a current "RNA first" model for the origin of life, RNA emerged in some form on early Earth to become the first biopolymer to support Darwinism here. Threose nucleic acid (TNA) and other polyelectrolytes are also considered as the possible first Darwinian biopolymer(s). This model is being developed by 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.1710778114
更新日期:2017-10-24 00:00:00
abstract::Water freezing on solid surfaces is ubiquitous in nature. Even though icing/frosting impairs the performance and safety in many processes, its mechanism remains inadequately understood. Changing atmospheric conditions, surface properties, the complexity of icing physics, and the unorthodox behavior of water are the pr...
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.1206121109
更新日期:2012-10-02 00:00:00
abstract::Lufenuron is an insect growth regulator insecticide mainly used for the control of the cat flea. To understand mechanisms of resistance to lufenuron, we have characterized lufenuron resistance in a natural population of Drosophila melanogaster. In this study we have used precise genetic mapping to identify a mechanism...
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.0503709102
更新日期:2005-09-06 00:00:00
abstract::It has been known for more than a century that increases in neuronal activity in the brain are reliably accompanied by changes in local blood flow. More recently it has been appreciated that these blood flow increases are accompanied by increases in glycolysis that are much greater than the increases in oxidative phos...
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.0510632103
更新日期:2006-02-07 00:00:00
abstract::Steroidogenic factor-1 (SF-1) and liver receptor homologue-1 (LRH-1) belong to the fushi tarazu factor 1 subfamily of nuclear receptors. SF-1 is an essential factor for sex determination during development and regulates adrenal and gonadal steroidogenesis in the adult, whereas LRH-1 is a critical factor for developmen...
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.0409482102
更新日期:2005-05-24 00:00:00
abstract::Rat, but not human, erythrocytes undergo fusion promoted by the membrane-mobility agent 2-(2-methoxyethoxy)-ethyl cis-8-(2-octylcyclopropyl)octanoate (A2C). The difference in behavior is correlated with rat erythrocyte membrane protein degradation caused by Ca2+-activated proteases. The human erythrocyte is deficient ...
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.80.24.7542
更新日期:1983-12-01 00:00:00
abstract::Approximately 15 per cent of the light chains from homogeneous immunoglobulins in patients with multiple myeloma contain an oligosaccharide group. Five human myeloma light chains that contained carbohydrate were studied. The sequence Asn-[unk]-Ser/Thr was at the site of carbohydrate attachment in all light chains. 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.66.3.975
更新日期:1970-07-01 00:00:00