Cores forms

Figure 4.3 In most a/p-barrel structures the eight p strands of the barrel enclose a tightly packed hydrophobic core formed entirely by side chains from the p strands. The core is arranged in three layers, with each layer containing four side chains from alternate p strands. The schematic diagram shows this packing arrangement in the a/p barrel of the enzyme glycolate oxidase, the structure of which was determined by Carl Branden and colleagues in Uppsala, Sweden.

The structure of these globular aggregates is characterized by a micellar core formed by the hydrophilic heads of the surfactant molecules and a surrounding hydrophobic layer constituted by their opportunely arranged alkyl chains whereas their dynamics are characterized by conformational motions of heads and alkyl chains, frequent exchange of surfactant monomers between bulk solvent and micelle, and structural collapse of the aggregate leading to its dissolution, and vice versa [2-7]. 

The presence of a polyinitiator has a small effect only in batch mode, whereas the polymer obtained in a semi-batch process is more strongly branched (DB=2/3 as compared to DB=0.465 without initiator) [40]. A similar result was found by Hanselmann et al. for ABj monomers in the presence of a core-forming molecule [79]. 

Pt75Re25 also adopts a core-shell structure such that a nearly pure Pt shell surrounds a more uniform core formed by Pt-Re... 

Figure 4.16 Double bond (a) Lewis model of two tetrahedra sharing an edge, (b) Domain model the two single electron pair domains of the double bond are pulled in toward each other by the attraction of the two carbon cores forming one four-electron double-bond domain with a prolate ellipsoidal shape, thereby allowing the two hydrogen ligands to move apart.

Block copolymer micelles in which the core-forming polymer blocks are able to crystallize are relatively similar to rod-coil copolymers. A significant part of these crystalline-core micelles is actually resulting from the self-assembly of rod-coil block copolymers. 

The commonly accepted pulsar model is a neutron star of about one solar mass and a radius of the order of ten kilometers. A neutron star consists of a crust, which is about 1 km thick, and a high-density core. In the crust free neutrons and electrons coexist with a lattice of nuclei. The star s core consists mainly of neutrons and a few percents of protons and electrons. The central part of the core may contain some exotic states of matter, such as quark matter or a pion condensate. Inner parts of a neutron star cool up to temperatures 108iT in a few days after the star is formed. These temperatures are less than the critical temperatures Tc for the superfluid phase transitions of neutrons and protons. Thus, the neutrons in the star s crust and the core from a superfluid, while the protons in the core form a superconductor. The rotation of a neutron superfluid is achieved by means of an array of quantized vortices, each carrying a quantum of vorticity... 

Bazan and Schrock were the first to use ROMP of norbornene to prepare star polymers [108], As the coupling agent of the living polymer they used a norbor-nadiene dimer that plays the role of difunctional core-forming monomer as shown below ... 

Unilamellar liposomes are nanoparticles made of a bilayer, most often phospholipidic, entrapping an internal aqueous core. Formed spontaneously in the presence of an excess of water and above the gel-to-liquid crystal phase tran-... 

Carver et al. propose that the middle mannose residue in the trimannosidic core forms hydrogen bonds with the protein whereas in the present study it is the a(l- 3) terminal mannose residue which forms additional stabilizing interactions with the protein. 

In a related example, the mixed-valence V2O3 core forms when vanadyl sulfate is oxidized in a pH = 7.5 HCOs /COs buffer. This complex has a reversible oxidation whose potential is pH dependent since the mixed-valence dimer forms by the following equilibrium (Fq. 6) ... 

A modification of the Keggin structure is seen in the heteropolyvanadates, [XV14042]9 (X = P, As). In these anions two extra V03+ groups are attached to opposite sides of die Keggin core forming a cluster of reduced charge (see Figure 13). 68... 

The many loops of wire wrapped around an iron core form what is known as an armature. The armature is connected to an assembly of paddle wheels called a turbine. Energy from wind or falling water can cause the turbine and thus the armature to rotate, but most commercial turbines are steam turbines, meaning they are driven by steam. To boil the water to create steam requires an energy source, which is usually a fossil fuel or a nuclear fuel. 

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