Abstract:
:We study static and dynamical properties that distinguish 2D crystals constrained to lie on a curved substrate from their flat-space counterparts. A generic mechanism of dislocation unbinding in the presence of varying Gaussian curvature is presented in the context of a model surface amenable to full analytical treatment. We find that glide diffusion of isolated dislocations is suppressed by a binding potential of purely geometrical origin. Finally, the energetics and biased diffusion dynamics of point defects such as vacancies and interstitials are explained in terms of their geometric potential.
journal_name
Proc Natl Acad Sci U S Aauthors
Vitelli V,Lucks JB,Nelson DRdoi
10.1073/pnas.0602755103subject
Has Abstractpub_date
2006-08-15 00:00:00pages
12323-8issue
33eissn
0027-8424issn
1091-6490pii
0602755103journal_volume
103pub_type
杂志文章abstract::RNA interference, mediated by small interfering RNAs (siRNAs), is a conserved regulatory process that has evolved as an antiviral defense mechanism in plants and animals. It is not known whether host cells also use siRNAs as an antibacterial defense mechanism in eukaryotes. Here, we report the discovery of an endogeno...
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.0608258103
更新日期:2006-11-21 00:00:00
abstract::Estrogen signaling occurs through at least two distinct molecular pathways: (i) direct binding of liganded estrogen receptors (ERs) to estrogen-responsive DNA elements (EREs) (the "ER/ERE pathway") and (ii) indirect recruitment of liganded ERs to activating protein-1 (AP-1)-responsive DNA elements via heterodimers of ...
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.0407113102
更新日期:2005-01-18 00:00:00
abstract::Ig class-switch recombination (CSR) is directed by the long and repetitive switch regions and requires activation-induced cytidine deaminase (AID). One of the conserved switch-region sequence motifs (AGCT) is a preferred site for AID-mediated DNA-cytosine deamination. By using somatic gene targeting and recombinase-me...
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.1018726108
更新日期:2011-07-12 00:00:00
abstract::We investigated the participation of genomic regulatory events in the response of the songbird brain to a natural auditory stimulus of known physiological and behavioral relevance, birdsong. Using in situ hybridization, we detected a rapid increase in forebrain mRNA levels of an immediate-early gene encoding a transcr...
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.89.15.6818
更新日期:1992-08-01 00:00:00
abstract::Bovine milk lipoprotein lipase was subjected to amino acid sequence analysis. The first 19 amino-terminal residues were Asp-Arg-Ile-Thr-Gly-Gly-Lys-Asp-Phe-Arg-Asp-Ile-Glu-Ser-Lys-Phe-Ala-Leu- Arg. In addition, reversed-phase high-performance liquid chromatography of a tryptic digest of reduced and alkylated lipase 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.83.12.4185
更新日期:1986-06-01 00:00:00
abstract::The functions of neurotransmitters in fetal development are poorly understood. Genetic observations have suggested a role for the inhibitory amino acid neurotransmitter gamma-aminobutyric acid (GABA) in the normal development of the mouse palate. Mice homozygous for mutations in the beta-3 GABAA receptor subunit devel...
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.94.21.11451
更新日期:1997-10-14 00:00:00
abstract::In this note the Weierstrass integral J is taken as L, the Riemann integral of length. Here M(n), n > 1, is a compact, connected manifold of class C(infinity) with a positive definite Riemann structure. Presentations (phi, U(phi)) in M(n) and geodesics (with the aid of the Euler-Riemann equations) are defined in Morse...
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.74.6.2209
更新日期:1977-06-01 00:00:00
abstract::BALB/c murine sarcoma Meth A is known to have three missense point mutations in p53. We previously reported that a nonamer peptide containing the codon 234 mutational product (designated 234CM) elicited 234CM-specific cytotoxic T cells and that immunization with 234CM in adjuvant before tumor challenge inhibited Meth ...
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.92.6.2219
更新日期:1995-03-14 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::Generating human single-nucleotide polymorphisms (SNPs) is no longer a rate-limiting step for genetic studies of disease. The number of SNPs in public databases already exceeds 200,000, and the total is expected to exceed 1,000,000 within a year. Rather, progress is limited by the inability to genotype large numbers o...
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.210394597
更新日期:2000-10-24 00:00:00
abstract::Some monoclonal antibodies (mAbs) against interleukin (IL) 1 alpha have been found to activate antigen-presenting cells (APC, human peripheral blood monocytes and B lymphocytes), so that unstimulated T lymphocytes cultured with them are induced to proliferate and secrete IL-2. Control mAbs of the same isotypes and mAb...
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.87.4.1305
更新日期:1990-02-01 00:00:00
abstract::The binding of a few molecules [1-6] of RNA bacteriophage coat protein to 1 molecule of RNA represses in vitro translation of the RNA synthetase cistron. Digestion of the complex, R17 coat protein-R17 RNA, by T1 RNase yields an RNA fragment bound to the coat protein. The nucleotide sequence of this fragment (59 residu...
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.69.10.3033
更新日期:1972-10-01 00:00:00
abstract::By commandeering cellular translation initiation factors, or destroying those dispensable for viral mRNA translation, viruses often suppress host protein synthesis. In contrast, cellular protein synthesis proceeds in human cytomegalovirus (HCMV)-infected cells, forcing viral and cellular mRNAs to compete for limiting ...
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.1202829109
更新日期:2012-04-10 00:00:00
abstract::The pharmacokinetic analysis of dynamic-contrast-enhanced (DCE) MRI data yields K(trans) and k(ep), two parameters independently measuring the capillary wall contrast reagent transfer rate. The almost universally used standard model (SM) embeds the implicit assumption that equilibrium transcytolemmal water exchange is...
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.0711226105
更新日期:2008-11-18 00:00:00
abstract::Obesity is associated with increased risk for developing pancreatic cancer, and it is suggested that insulin resistance provides the missing link. Here we demonstrate that under the context of genetic susceptibility, a high fat diet (HFD) predisposes mice with oncogenic K-ras activation to accelerated pancreatic intra...
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.0802864106
更新日期:2009-03-03 00:00:00
abstract::The DNA-containing Epstein-Barr herpesvirus has been implicated in the etiology of Burkitt's lymphoma, a malignant tumor of children in Africa. Recently, however, particles possessing four biochemical characteristics of RNA tumor viruses have also been identified in these tumors. The fact that both types of viruses ar...
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.70.11.3175
更新日期:1973-11-01 00:00:00
abstract::During the last 15 years several laboratories have attempted to generate rabbit monoclonal antibodies, mainly because rabbits recognize antigens and epitopes that are not immunogenic in mice or rats, two species from which monoclonal antibodies are usually generated. Monoclonal antibodies from rabbits could not be gen...
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.92.20.9348
更新日期:1995-09-26 00:00:00
abstract::Cytochrome ba3 from Thermus thermophilus reacts slowly with excess HCN at pH 7.4 to create a form of the enzyme in which CuA, cytochrome b, and CuB remain oxidized, while cytochrome a3 is reduced by one electron, presumably with the formation of cyanogen. We have examined this form of the enzyme by UV-visible, resonan...
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.89.8.3195
更新日期:1992-04-15 00:00:00
abstract::Osteoclasts, bone-resorptive multinucleated cells derived from hematopoietic stem cells, are associated with many bone-related diseases, such as osteoporosis. Osteoclast-targeting small-molecule inhibitors are valuable tools for studying osteoclast biology and for developing antiresorptive agents. Here, we have discov...
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.0712239105
更新日期:2008-08-19 00:00:00
abstract::Transcript accumulation and translation of psbA as well as processing of the D1 precursor protein were investigated in relation to chlorophyll availability in vivo in cyanobacterial strains lacking photosystem I (PS I). The psbA transcript level was almost independent of chlorophyll availability and was approximately ...
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.95.10.5830
更新日期:1998-05-12 00:00:00
abstract::Peroxisome proliferators cause rapid and coordinated transcriptional activation of genes encoding peroxisomal beta-oxidation system enzymes by activating peroxisome proliferator-activated receptor (PPAR) isoform(s). Since the thyroid hormone (T3; 3,3',5-triiodothyronine) receptor (TR), another member of the nuclear ho...
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.92.25.11593
更新日期:1995-12-05 00:00:00
abstract::We demonstrate remote detection of nuclear magnetic resonance (NMR) with a microchip sensor consisting of a microfluidic channel and a microfabricated vapor cell (the heart of an atomic magnetometer). Detection occurs at zero magnetic field, which allows operation of the magnetometer in the spin-exchange relaxation-fr...
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.0711505105
更新日期:2008-02-19 00:00:00
abstract::Human declarative memory involves a systematic organization of information that supports generalizations and inferences from acquired knowledge. This kind of memory depends on the hippocampal region in humans, but the extent to which animals also have declarative memory, and whether inferential expression of memory de...
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.94.13.7109
更新日期:1997-06-24 00:00:00
abstract::Complex liquids flow through channels faster than expected, an effect attributed to the formation of low-viscosity depletion layers at the boundaries. Characterization of depletion layer length scale, concentration, and dynamics has remained elusive due in large part to the lack of suitable real-space experimental tec...
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.1900623116
更新日期:2019-08-13 00:00:00
abstract::Incubation of rat calvaria for short times in the presence of a labeled amino acid revealed the existence of a collagen fraction (procollagen) that functions as a biosynthetic precursor of collagen. Procollagen contains an alpha1-like chain (pre-alpha1) that elutes earlier from CM-cellulose than does rat-bone alpha1 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.68.6.1138
更新日期:1971-06-01 00:00:00
abstract::Obesity is a major public health problem and is often associated with type 2 diabetes mellitus, cardiovascular disease, and metabolic syndrome. Leptin is the crucial adipostatic hormone that controls food intake and body weight through the activation of specific leptin receptors (OB-R) in the hypothalamic arcuate nucl...
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.0706671104
更新日期:2007-12-04 00:00:00
abstract::Attention allows animals to respond selectively to competing stimuli, enabling some stimuli to evoke a behavioral response while others are ignored. How the brain does this remains mysterious, although it is increasingly evident that even animals with the smallest brains display this capacity. For example, insects res...
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.1323297111
更新日期:2014-04-01 00:00:00
abstract::Methylation on lysine 9 of histone H3 (H3K9me) and DNA methylation play important roles in the transcriptional silencing of specific genes and repetitive elements. Both marks are detected on class I and II endogenous retroviruses (ERVs) in murine embryonic stem cells (mESCs). Recently, we reported that the H3K9-specif...
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.1014660108
更新日期:2011-04-05 00:00:00
abstract::Genome packaging is an essential step in virus replication and a potential drug target. Single-stranded RNA viruses have been thought to encapsidate their genomes by gradual co-assembly with capsid subunits. In contrast, using a single molecule fluorescence assay to monitor RNA conformation and virus assembly in real ...
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.1204357109
更新日期:2012-09-25 00:00:00
abstract::Inadequate resolution is the principal limitation of radiocarbon dating. However, recent work has shown that exact-year precision is attainable if use can be made of past increases in atmospheric radiocarbon concentration or so-called Miyake events. Here, this nascent method is applied to an archaeological site of pre...
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.1921301117
更新日期:2020-06-23 00:00:00