Search results for "Plate"

Metals in supramolecular chemistry

2014

Abstract Metals have played a fundamental role in the development of supramolecular chemistry. The main steps taken from the pre-supramolecular age to the present time are retraced with a brief description of salient examples from the unconscious use of gold nanoparticle in the preparation of the Lycurgus cup (5th or 4th century B.C.) to the modern use of metals as templates, for the preparation of large self-assembled structures, of molecular sensors, switches, motors and machines, for mimicking biological processes, for tissue and organ imaging or for the application of the Boolean logic at the molecular level.

Crystal‐Structure Studies of Mononuclear Iron(II) Complexes with Two‐Step Spin Crossover: [Fe{5‐NO 2 ‐sal‐N(1,4,7,10)}] Revisited

2013

In the region of the spin transition of spin-crossover (SCO) compounds there coexist molecules in both high-spin (HS) and low-spin (LS) states. In the case of two-step spin transition, theoretical predictions and computer simulations have shown that HS and LS complex molecules should be ordered in the plateau region. Several examples that support this hypothesis are already presented in the literature. Herein, we discuss a mononuclear complex of iron(II) with two-step spin transition in terms of long-range ordering of HS and LS molecules. In such compounds, spin transition is associated with the formation of a superstructure. However, previous studies of the [Fe{5-NO2-sal-N(1,4,7,10)}] [5-N…

pH‐Controlled Assemblies of Dimethyltin‐Functionalized 9‐Tungstophosphates with Guanidinium as Structure‐Directing Cation

2010

Aqueous reaction of (CH 3 ) 2 SnCl 2 with Na 9 [A-α-PW 9 O 34 ] in a 3:1 ratio with [C(NH 2 ) 3 ] + as structure-directing agent resulted in three distinct assemblies of dimethyltin-functionalized tungstophosphates depending on the pH: [{(CH 3 ) 2 -Sn(H 2 O)}{(CH 3 ) 2 Sn}(A-α-PW 9 O 34 )] 5- ( 1 ) at pH = 4.5; [{(CH 3 ) 2 -Sn(H 2 O) 2 }{(CH 3 ) 2 Sn(H 2 O)} 2 (A-α-PW 9 O 34 )] 3- (2) at pH = 3.0; and [{(CH 3 ) 2 Sn(H 2 O)} 3 (A-α-PW 9 O 34 )] 3- (3) at pH = 2.0. All three compounds have been characterized in the solid-state by elemental and thermal analyses, infrared spectroscopy and single-crystal X-ray diffraction. The [A-α-PW 9 O 34 ] 9- trilacunary fragments have three {(CH 3 ) 2 Sn} 2…

MMGBSA As a Tool To Understand the Binding Affinities of Filamin–Peptide Interactions

2013

Filamins (FLN) are large dimeric proteins that cross-link actin and work as important scaffolds in human cells. FLNs consist of an N-terminal actin-binding domain followed by 24 immunoglobulin-like domains (FLN1-24). FLN domains are divided into four subgroups based on their amino acid sequences. One of these subgroups, including domains 4, 9, 12, 17, 19, 21, and 23, shares a similar ligand-binding site between the β strands C and D. Several proteins, such as integrins β2 and β7, glycoprotein Ibα (GPIbα), and migfilin, have been shown to bind to this site. Here, we computationally estimated the binding free energies of filamin A (FLNa) subunits with bound peptides using the molecular mechan…

The collagen receptor integrins have distinct ligand recognition and signaling functions

2000

Distinct collagen subtypes are recognized by specific cell surface receptors. Two of the best known collagen receptors are members of the integrin family and are named alpha1beta1 and alpha2beta1. Integrin alpha1beta1 is abundant on smooth muscle cells, whereas the alpha2beta1 integrin is the major collagen receptor on epithelial cells and platelets. Many cell types, such as fibroblasts, osteoblasts, chondrocytes, endothelial cells, and lymphocytes may concomitantly express both of the receptors. We have studied the cell biology of these integrins at two levels. First, we have analyzed their ligand binding mechanism and specificity. Second, we have studied their signaling function inside th…

On the origin of Metazoan adhesion receptors: cloning of integrin alpha subunit from the sponge Geodia cydonium

1997

Integrins are prominent receptors known from vertebrates and the higher phyla of invertebrates. Until now, no evidence has been provided for the existence of integrins in the lowest Metazoa, the sponges (Porifera). We have isolated and characterized a cDNA clone encoding the alpha subunit of integrin from the marine sponge Geodia cydonium (GCINTEG). The open reading frame encodes a polypeptide of 1,086 residues (118 kDa). The intracellular domain features the sequence Tyr-Phe-x-Gly-Phe-Phe-x-Arg, which is different in one residue from the characteristic consensus pattern for integrin alpha subunits. We conclude that sponges, the oldest multicellular animal phylum, already utilize the struct…

Cross-talk between minimally primed HL-60 cells and resting HUVEC reveals a crucial role for adhesion over extracellularly released oxidants

2011

This study demonstrates that a long-lasting co-culture of neutrophil surrogates (HL-60 cells), minimally primed by platelet activating factor (PAF), and resting endothelial cells (EC) results in the elaboration of an hyper-adhesive endothelial surface, as measured by the increase in the expression of endothelial adhesion molecules E-Selectin, VCAM-1, and ICAM-1. This endothelial dysfunction is mediated by the activation of the redox-sensitive transcription factor NF-κB through an exclusive adhesion-driven mechanism active in the endothelial cell: reactive oxygen and nitrogen species, extracellularly released by minimally primed HL-60 cells, are not involved in the induction of the endotheli…

Loi Avia : une censure attendue mais paradoxalement surprenante

2020

International audience

NOVEL TOOLS FOR THE MECHANICAL ANALYSIS OF THIN PLATES AND RELEVANCE ON MEMBRANE-BASED TECHNOLOGIES

2020

Age of initial oceanic magmatism in the Late Proterozoic Arabian Shield

1992

Lead isotopic data for zircons from a dacite clast in a volcanic breccia of the oldest oceanic assemblage (immature arc or oceanic plateau) of the southwestern Arabian Shield (Baish group), acquired with the single-grain evaporation technique, yielded a mean 207 Pb/ 206 Pb age of 842 ±17 Ma. Earlier published Rb-Sr data for Baish rocks yielded a three-point isochron of 1165 ±110 Ma. This age has been repeatedly cited as evidence for pre-1 Ga arc magmatism in the Arabian Shield. However, more recent Rb-Sr data and zircon ages for clastic metasedimentary rocks are in agreement with our new zircon age, suggesting that initial oceanic magmatism in the Arabian Shield did not begin until after 90…