Abstract:
:We stabilize nematic droplets with handles against surface tension-driven instabilities, using a yield-stress material as outer fluid, and study the complex nematic textures and defect structures that result from the competition between topological constraints and the elasticity of the nematic liquid crystal. We uncover a surprisingly persistent twisted configuration of the nematic director inside the droplets when tangential anchoring is established at their boundaries, which we explain after considering the influence of saddle splay on the elastic free energy. For toroidal droplets, we find that the saddle-splay energy screens the twisting energy, resulting in a spontaneous breaking of mirror symmetry; the chiral twisted state persists for aspect ratios as large as ∼20. For droplets with additional handles, we observe in experiments and computer simulations that there are two additional -1 surface defects per handle; these are located in regions with local saddle geometry to minimize the nematic distortions and hence the corresponding elastic free energy.
journal_name
Proc Natl Acad Sci U S Aauthors
Pairam E,Vallamkondu J,Koning V,van Zuiden BC,Ellis PW,Bates MA,Vitelli V,Fernandez-Nieves Adoi
10.1073/pnas.1221380110subject
Has Abstractpub_date
2013-06-04 00:00:00pages
9295-300issue
23eissn
0027-8424issn
1091-6490pii
1221380110journal_volume
110pub_type
杂志文章abstract::USF is a family of transcription factors characterized by a highly conserved basic-helix-loop-helix-leucine zipper (bHLH-zip) DNA-binding domain. Two different USF genes, termed USF1 and USF2, are ubiquitously expressed in both humans and mice. The USF1 and USF2 proteins contain highly divergent transcriptional activa...
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.93.3.1308
更新日期:1996-02-06 00:00:00
abstract::West Nile virus, which is transmitted by Culex mosquitoes while feeding on birds and humans, has emerged as the dominant vector borne disease in North America. We have identified natural compounds from humans and birds, which are detected with extreme sensitivity by olfactory receptor neurons (ORNs) on the antennae 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.0906932106
更新日期:2009-11-03 00:00:00
abstract::During tRNA biosynthesis the 5'-leader sequences in precursor tRNAs are removed by the ribonucleoprotein RNase P, an enzyme whose RNA moiety is required for activity. To clarify some aspects of the enzyme mechanism, we examined substrate binding and product formation with mutant precursor tRNAs. Mutations G-1----A or ...
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.85.5.1379
更新日期:1988-03-01 00:00:00
abstract::The present studies were conducted to determine whether prostaglandin F2 alpha (PGF2 alpha) stimulates the production of "second messengers" derived from inositol phospholipid hydrolysis and increases intracellular free Ca2+ ([Ca2+]i) in isolated bovine luteal cells. PGF2 alpha provoked rapid (10 sec) and sustained (u...
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.84.11.3728
更新日期:1987-06-01 00:00:00
abstract::Retinoic acid is a morphogenetic signaling molecule derived from vitamin A and involved in vertebrate development. Two groups of receptors, retinoic acid receptors and retinoid X receptors (RXRs), have been identified. All-trans-retinoic acid is the high-affinity ligand for retinoic acid receptors, and 9-cis-retinoic ...
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.90.13.6170
更新日期:1993-07-01 00:00:00
abstract::Schaftoside and isoschaftoside are bioactive natural products widely distributed in higher plants including cereal crops and medicinal herbs. Their biosynthesis may be related with plant defense. However, little is known on the glycosylation biosynthetic pathway of these flavonoid di-C-glycosides with different sugar ...
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.2012745117
更新日期:2020-12-01 00:00:00
abstract::Scientific journal publications, and their contributions to knowledge, can be described by their depth (specialized, domain-specific knowledge extensions) and breadth (topical scope, including spanning multiple knowledge domains). Toward generating hypotheses about how scientists' personal dispositions would uniquely ...
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.1421286112
更新日期:2015-03-24 00:00:00
abstract::A common genetic mutation found in clear cell renal cell carcinoma (CC-RCC) is the loss of the von Hippel-Lindau (VHL) gene, which results in stabilization of hypoxia-inducible factors (HIFs), and contributes to cancer progression and metastasis. CUB-domain-containing protein 1 (CDCP1) was shown to promote metastasis ...
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.1011777108
更新日期:2011-02-01 00:00:00
abstract::Clostridium ljungdahlii is an anaerobic homoacetogen, able to ferment sugars, other organic compounds, or CO(2)/H(2) and synthesis gas (CO/H(2)). The latter feature makes it an interesting microbe for the biotech industry, as important bulk chemicals and proteins can be produced at the expense of CO(2), thus combining...
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.1004716107
更新日期:2010-07-20 00:00:00
abstract::Each G protein-coupled receptor recognizes only a distinct subset of the many structurally closely related G proteins expressed within a cell. How this selectively is achieved at a molecular level is not well understood, particularly since no specific point-to-point contact sites between a receptor and its cognate G 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.92.25.11642
更新日期:1995-12-05 00:00:00
abstract::Grain yield in many cereal crops is largely determined by grain size. Here we report the genetic and molecular characterization of GS3, a major quantitative trait locus for grain size. It functions as a negative regulator of grain size and organ size. The wild-type isoform is composed of four putative domains: a plant...
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.1014419107
更新日期:2010-11-09 00:00:00
abstract::Legionella pneumophila causes a potentially fatal form of pneumonia by replicating within macrophages in the Legionella-containing vacuole (LCV). Bacterial survival and proliferation within the LCV rely on hundreds of secreted effector proteins comprising high functional redundancy. The vacuolar membrane-localized Mav...
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.1902806116
更新日期:2019-09-03 00:00:00
abstract::A Ca2+-channel blocker derived from funnel-web spider toxin (FTX) has made it possible to define and study the ionic channels responsible for the Ca2+ conductance in mammalian Purkinje cell neurons and the preterminal in squid giant synapse. In cerebellar slices, FTX blocked Ca2+-dependent spikes in Purkinje cells, 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.86.5.1689
更新日期:1989-03-01 00:00:00
abstract::Whole-cell DNA preparations isolated from SC-1 cells chronically infected with N- or B-tropic murine leukemia viruses (MuLV) were tested for infectious activity in an Fv-1n (NIH-3T3) and two Fv-Ib (C57BL/6 and SV-A31) cell cultures. Efficiency of transfection for all DNAs was better in the NIH-3T3 cells than in C57BL/...
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.75.3.1451
更新日期:1978-03-01 00:00:00
abstract::Blot hybridization analysis that used labeled tubulin cDNA probes revealed that N6,O2'-dibutyryladenosine 3',5'-cyclic monophosphate [dibutyryl cyclic AMP (Bt2cAMP)] initially increases and later decreases the level of tubulin mRNA in a neuroblastoma-glioma hybrid cell line as well as in the parent cells. A significan...
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.80.14.4243
更新日期:1983-07-01 00:00:00
abstract::Substrate rigidity affects many physiological processes through mechanochemical signals from focal adhesion (FA) complexes that subsequently modulate gene expression. We find that shuttling of the LIM domain (domain discovered in the proteins, Lin11, Isl-1, and Mec-3) protein four-and-a-half LIM domains 2 (FHL2) betwe...
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.1608210113
更新日期:2016-11-01 00:00:00
abstract::The origin of plant chemical ecology generally dates to the late 1950s, when evolutionary entomologists recognized the essential role of plant secondary metabolites in plant-insect interactions and suggested that plant chemical diversity evolved under the selection pressure of herbivory. However, similar ideas had alr...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 传,历史文章,杂志文章
doi:10.1073/pnas.0709231105
更新日期:2008-03-25 00:00:00
abstract::Integral membrane proteins that form water-filled channels through membranes often exist as aggregates of similar or identical subunits spanning the membrane. It has been suggested that the insertion into the membrane of the channel-forming domains of the subunits may impart unusual structural features to the membrane...
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.82.4.958
更新日期:1985-02-01 00:00:00
abstract::We have measured high-resolution x-ray absorption spectra of lanthanide (Ln) and heavy transition metal complexes that display prominent narrow absorption peaks near the L2 and L3 absorption edges. The anomalous scattering factors (f' and f"), which are mathematically related to the absorption cross section, have corr...
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.77.10.5884
更新日期:1980-10-01 00:00:00
abstract::Bar-coded multiplexed sequencing approaches based on new-generation sequencing technologies provide capacity to sequence a mapping population in a single sequencing run. However, such approaches usually generate low-coverage and error-prone sequences for each line in a population. Thus, it is a significant challenge 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.1005931107
更新日期:2010-06-08 00:00:00
abstract::The immunity protein to colicin A (Cai), which is constitutively expressed at a very low level in Escherichia coli strains, has been studied in recombinant plasmid constructs allowing expression of various immunity fusion proteins under the control of inducible promoters. The 13-amino acid NH2-terminal region of Cai 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.85.3.689
更新日期:1988-02-01 00:00:00
abstract::Stearoyl-acyl-carrier-protein-desaturase-mediated conversion of stearic acid (18:0) to oleic acid (18:1) is a key step, which regulates levels of unsaturated fatty acids in cells. We previously showed that stearoyl-acyl-carrier-protein-desaturase mutants ssi2/fab2 carrying a loss-of-function mutation in the plastidial...
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.0401315101
更新日期:2004-04-06 00:00:00
abstract::Integrin alphanubeta3 is found on a subset of tumor blood vessels where it is associated with angiogenesis and malignant tumor growth. We designed an alphanubeta3-targeted nanoparticle (NP) encapsulating the cytotoxic drug doxorubicin (Dox) for targeted drug delivery to the alphanubeta3-expressing tumor vasculature. 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.0803728105
更新日期:2008-07-08 00:00:00
abstract::Inbred Lewis (LEW/N) female rats develop an arthritis in response to group A streptococcal cell wall peptidoglycan polysaccharide (SCW), which mimics human rheumatoid arthritis. Histocompatible Fischer (F344/N) rats do not develop arthritis in response to the same SCW stimulus. To evaluate this difference in inflammat...
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.86.7.2374
更新日期:1989-04-01 00:00:00
abstract::Ovine pulmonary surfactant is bactericidal for Pasteurella haemolytica when surfactant and bacteria mixtures are incubated with normal ovine serum. To isolate this component, surfactant (1 mg/ml) was centrifuged at 100,000 x gav, and the supernatant was fractionated by HPLC. Fractions were eluted with acetonitrile (10...
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.93.1.412
更新日期:1996-01-09 00:00:00
abstract::Block of Ca2+ currents by the dihydropyridine drug nitrendipine was studied in single canine ventricular cells by using the whole-cell variant of the patch clamp technique. When cells were held at depolarized membrane potentials at which Ca2+ currents were approximately equal to 70% inactivated, nitrendipine blocked C...
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.81.20.6388
更新日期:1984-10-01 00:00:00
abstract::Increased intestinal permeability has been observed in numerous human autoimmune diseases, including type-1 diabetes (T1D) and its' animal model, the BB-wor diabetic prone rat. We have recently described zonulin, a protein that regulates intercellular tight junctions. The objective of this study was to establish wheth...
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.0500178102
更新日期:2005-02-22 00:00:00
abstract::The gene EPXH2 encodes for the soluble epoxide hydrolase (sEH), an enzyme involved in the regulation of cardiovascular and renal physiology containing two distinct domains connected via a proline-rich linker. The C-terminal domain containing the EH catalytic activity has been well studied. In contrast, a function for ...
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.0437724100
更新日期:2003-02-18 00:00:00
abstract::Sympatric speciation has been controversial since it was first proposed as a mode of speciation. Subterranean blind mole rats (Spalacidae) are considered to speciate allopatrically or peripatrically. Here, we report a possible incipient sympatric adaptive ecological speciation in Spalax galili (2n = 52). The study mic...
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.1222588110
更新日期:2013-02-12 00:00:00
abstract::The exo isomer of aflatoxin B1 (AFB1) 8,9-epoxide appears to be the only product of AFB1 involved in reaction with DNA and reacts with the N7 atom of guanine via an SN2 reaction from an intercalated state. Although the epoxide hydrolyzes rapidly in H2O (0.6 s-1 at 25 degrees C), very high yields of DNA adduct result. ...
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.94.12.6121
更新日期:1997-06-10 00:00:00